Thermionic discharge device



Aug. 27, 1935. J, ETE zmmw- THERMIONIC DISCHARGE DEVICE Filed Aug. 150,1923 u WITNESSES: INVENTOR Mw 10/10 F e fen? ATTORNEY Patented Aug. 27,1935 v 1 UNITED STATES PATENT OFFICE)? THERMIONIC' DISCHARGE DEVICE JohnF. Peters, Pittsburgh, Pa., assignor to Westinghouse Electric &Manufacturing Company, a corporation of Pennsylvania Application August30, 1923, Serial No. 660,093

. 4Claims. (Cl. 250-275) My invention relates to thermionic dischargenetic modulation efiect which occurswith the devices. single filamentwhen heated by alternating cur- Broadly speaking, the object of myinvention rent. is to provide a cathode for a thermionic discharge Otherobjects and structural details of my in- 5 device which avoids thedifiiculties encountered vention will be apparent from the following de-5 in heating thermionic cathodes by alternating scription and claimswhen read in connection current. with the accompanying drawings,wherein:

More specifically, the object of my invention is Figure 1 is a view inelevation of a cathode conto provide a heated cathode construction for astructed according to my invention. thermionic discharge device in whichmeans are Fig. 2 is a view in elevation of a vacuum tube 10 providedwhereby the cathode can be heated by having a cathode constructedaccording to my alternating current and means whereby the modinventionin operative relation to a fiat grid and ulating effect of thealternating magnetic field plate of the pattern employed in a typicaltriode, produced by alternating current as encountered and in the usualsingle filament cathode structure of Fig. 3 is a view similar to Fig. 2illustrating the 15 the'prior art is nullified. cathode in conjunctionwith a cylindrical grid In thermionic discharge devices constructed andcylindrical plate. according to the prior art,asingle filament is cus-In the figures, similar structures have the tomarily used. This filamentis usually heated same reference numbers. by a flow of low voltagedirect current. Many In the structure of Fig. 1, a press I carries 20such devices have been constructed with a filasealed-in conductor andsupporting wires 2, 3, 4, ment cathode of such size as to be heated tothe 5 and 6. Two adjacent filaments I and 8 are operating temperature bya current of approxi attached at their ends to conductor wires 3 andmately one ampere, supplied at a voltage of ap- 5 and are supported attheir centers by supportproximately 6 volts. This current is customarilying wire 2. Wires II and I2 serve as connectors 25 supplied from astorage battery. However, it for conducting the current from the leadwires would be much more convenient to supply the 3 and 5 to the ends offilaments l and 8.

heating energy as alternating current from com- In the arrangement shownin Fig. 2, a press I mercial frequency circuits by a transformer at a isprovided, as before. Lead and supporting wires suitable voltage. 2, 3,4, 5, 6, l3 and M are also provided as are 30 When this s been attemptedin the pas filaments l and 8. In addition, a grid I5 suphowever,difliculties have been experienced due ported n wires 6 and I4 and aplate 5 supported to the fact that the magnetic field incident to any nwire 4 and I3 are provided, A container 11 heating Current produces linfluence p n the of glass or other suitable material is provided.

electron stream. When direct current is used for Th structure of Fig. 3is similar to that of 35 a hea r y pp y h ma n i efiect i Fig. 2 exceptthat a cylindrical grid 2| and a S a and Steadyinvalue, and therefore,produces cylindrical plate 22 are provided instead of the no pulsatingmodulation effect on the electron fiat grid and plate. stream to berecognized as a sound in the receiv- I the operation of my device, analternating i c app atus p y d i njun ti n with t current source isconnected to leads 3 and 5. 40 tube. When, howeve alternatingCurrentisused Current fiows between the leads by way of filawith asingle filament cathode, the pulsations of ments 1 and 3 in Such mannert t t reSPecthe curren p d a Varying magnetic effect tive portions ofthe filaments of opposite polarity p the electmn Stream which causes aagand in juxtaposition to each other carry currents netic modu a on andis perceived as a und in in opposite directions. Potential is alsoimpressed 45 a telephone device employed in Conjunctifln Wi between thefilament structure and an adjacent the system containing such filamentcathode. anode structure, whereupon an electron stream My inventionprovides a cathode construction carries the current between the anodeand the consisting of two filaments placed in juxtaposicathode.Modulation of this electron stream by tion, and connected to the sameenergy source in a magnetic field produced by the alternating cur- 50such way that they carry substantially equal rent in the filamentcathode structure is, howcurrents in opposite directions. These oppositeever, avoided by reason of the neutralization of currents produceopposing magnetic fields. the field of one filament by the field of theadja- These fields, by virtue of their opposition, neucent filament.

56 tralize each other and thereby avoid the mag While I have illustratedbut one embodiment of my invention, it will be apparent to those skilledin the art that various changes and modifications may be made withoutdeparting from the spirit and scope of my invention and it is desired,therefore that only such limitations shall be imposed thereon as areindicated in the prior art or as set forth in the appended claims.

I claim as my invention:

1. Air electron-discharge device comprising a cathodestructure havingmore than two currentcarrying members comprising two groups to carrycurrent in opposite directions, individual members of one group beingmore closely adjacent to a member of the other group than to any memberof their own group. H

2. An electron-discharge device comprising a cathode structure having apair of current-carrying loops, the sides of each" loop being more distant from that side of the other loop which car ries current of the samedirection than from that side of the other loop which carries current ofthe opposite direction.

3. An electron-discharge-tube device comprising a cathode having twosubstantially hair-pinshaped filaments, said filaments crossing eachother at their bights, a common support for said bights, the sides ofeach filament being relatively far apart from each other, eachfilament-side being farther from that side of the other-filament whichcarries current inthe samedirection than from that side of the otherfilament that carries current in the opposite direction as itself.

4. A thermionic tube having plate and grid element's therein, an evennumber of filaments, and connections for conveying a heating current tosaid filaments, each of said filaments having a part lying substantiallyalongside a neighboring filament, and connected to cause theinstantaneous direction of flow in such parts of the two filaments to besubstantially opposite.

JOHN PETERS.

